Former prime ministers David Cameron and Tony Blair have warned against plans to cut the overseas aid budget, calling the idea a “strategic mistake”. The chancellor, Rishi Sunak, is widely expected to pare back the UK’s commitment to spend 0.7% of national income on overseas aid to 0.5% in next week’s spending review. Cameron oversaw the country meeting the 0.7% target for the first time in 2013, and he and Blair have joined a list of those urging a rethink of the plans. The spending on aid is related to gross national income, which in 2019 was £2.17tn, meaning a drop from 0.7% to 0.5% would account for more than £4bn. But Cameron told the Daily Telegraph: “Abandoning the 0.7% target for aid would be a moral, strategic and political mistake. Moral, because we should be keeping our promises to the world’s poorest. A strategic error, because we would be signalling retreat from one of the UK’s vital acts of global leadership. “And a political mistake because the UK is about to chair the G7 and important climate change negotiations. I hope the PM will stick to his clear manifesto promise, maintain UK leadership and save lives.” Last week, the prime minister’s official spokesman drew attention to the fact that the legislation enshrining the 0.7% target in UK law explicitly acknowledged it might not always be met. Meanwhile, coronavirus has led to a strain on the public purse with the government spending billions attempting to keep the economy ticking over. Blair said foreign aid – and the 0.7% target – had been a “great British soft power achievement” and that it had saved millions of lives in Africa by reducing deaths from malaria and HIV. He told the Telegraph: “It’s enlightened self-interest. Neither the challenge of climate or Covid-19 can be met without Africa. Nor can those of extremism and uncontrolled immigration. To change it is a profound strategic mistake.” Earlier this week, Johnson was urged to rethink the plan in a letter signed by 185 development and humanitarian charity leaders including Save The Children, Greenpeace UK, and Unicef UK. “Now is not the time to renege on our promise to spend 0.7% of our gross national income on aid and development,” they said. “Stepping back from our international commitments is not the solution and risks damaging the UK’s standing globally as we define our role in the world post-Brexit. “A U-turn on your manifesto commitment to maintain the 0.7% target would signal we are a nation willing to balance its books on the backs of the world’s most marginalised people, many of whom are dealing with the impact of Covid-19 on top of existing hardship.”